The present invention relates to a rotary internal combustion engine and, in particular, to the cooling system therefore.
In conventional rotary internal combustion engines, a substantial amount of heat energy is absorbed by the coolant and then lost to the environment. It would be desirable to reduce the amount of heat rejected into the coolant with the result that more energy would be available in the exhaust for turbocharging or turbocompounding. Also, in conventional rotary engines, water coolant passages are cast into the engine housing. Casting techniques require that certain minimum wall thicknesses be maintained between adjacent voids. Conventional engines also typically have relatively large coolant passages. These large coolant passages must be enclosed by relatively large amounts of solid housing material. This increases engine weight and interferes with heat transfer to the coolant. With such large coolant passages, coolant flow velocity is low, with the result that oil or fuel cannot be used as the coolant. It would be desirable to have an engine with coolant passages which are smaller so that oil or fuel could be used as the coolant and so that the amount of solid housing material in the engine can be reduced.